This raises a couple more questions for me.
First, when searching I was able to find Martin Fenner's very interesting blog posts about ideas for a "Scholarly Markdown" and, as those issues and the first link on the scholarlymarkdown.com site reference, he appears to be associated with a separate "scholmd" project, also called "Scholarly Markdown," which is apparently a related project that itself is a fork of the Python markdown science project:
scholmd:
Markdown Science:
https://github.com/karthik/markdown_science
However, it's unclear what all of the relationships are between all of these projects and forks.
Secondly, since some (or all?) of the changes are being discussed in the Pandoc issue tracker, are these changes intended to be submitted to Pandoc in pull requests? I don't currently see any.